Surgical stapler

ABSTRACT

There is disclosed a surgical stapler. An anvil is mounted on a distal end portion of an elongated body of the stapler. A guide member supports a number of staples disposed in contiguous relation to one another. The staples are urged toward the anvil by an urging mechanism. A ram is mounted on the body for movement along the longitudinal axis of the body. A lever is pivotally mounted on the body, and the pivotal movement of the lever is converted into a rectilinear movement of the ram by a motion converting mechanism. The ram, when advanced, cooperates with the anvil to deform the staple disposed in a path of movement of the ram. In order to achieve a lightweight and small-size construction of the stapler, the lever is pivotally connected at its proximal end to the proximal end portion of the body so that the lever is pivotally movable toward and away from the body, and a distal end portion of the lever serves as a manipulating portion. A mid portion of the lever spaced apart from the manipulating portion acts on the motion converting mechanism. Also, in order to achieve the above purpose, a guide passage for guiding an urging member of the urging mechanism has a curved portion, and the urging member has a flexible portion which can be guided by the curved portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a surgical stapler for suturing or sewing up awound or the like.

2. Prior Art

Japanese Laid-Open (Kokai) Patent Application No. 64782/76(corresponding to U.S. patent application Ser. No. 516,112 filed Oct.18, 1974), Japanese Patent Publication No. 4535/86 (corresponding toGerman Patent Application No. 3204522.0 filed Feb. 10, 1982) andJapanese Patent Publication No. 37983/87 (corresponding to U.S. patentapplication Ser. No. 374,692 filed May 4, 1982) disclose gun-shapedstaplers. Such a conventional stapler comprises a body having a gripportion and an elongated portion extending generally perpendicularlyfrom one end of the grip portion. A ram is mounted within the elongatedportion so as to be slidable along the length of the elongated portion.A trigger member is movably supported on the grip portion. When thetrigger member is urged toward the grip portion, the force thus appliedto the trigger member is transmitted to the ram through aforce-increasing means mounted within the body, so that the ram advancesto cooperate with an anvil, mounted at the distal end of the elongatedportion, to deform a staple. Such a conventional stapler isdisadvantageous in that it is of a large size and heavy in weight.

Japanese Patent Publication No. 6773/81 corresponding to U.S. patentapplication Ser. No. 742,843 filed Nov. 18, 1976), Japanese PatentPublication No. 38692/86 (corresponding to U.S. patent application Ser.No. 229,080 filed Jan. 28, 1981) and Japanese Patent Publication No.36694/87 (corresponding to U.S. patent application Ser. No. 961,740filed Nov. 17, 1978) disclose staplers which comprise an elongated bodyand a lever which are pivotally connected together at their distal ends.The distal end of the lever is engaged with a ram. When the lever isurged toward the body while the lever and the body are gripped by theoperator, the ram is advanced through the leverage of the lever under astrong force, so that the ram cooperates with an anvil to deform astaple. This type of conventional stapler is also disadvantageous inthat it is of a large size and heavy in weight.

A lightweight and small-size stapler is disclosed in Japanese PatentPublication No. 164050/84 (corresponding to U.S. patent application Ser.No. 470,066 filed Feb. 28, 1983). This conventional stapler comprises anelongated body, and a drive member (which corresponds to the lever ofthe above-mentioned conventional staplers) which is foldable at its midportion so as to serve as a toggle joint mechanism. The proximal endportion of the drive member is pivotally supported by the proximal endportion of the body, and the distal end portion of the drive member ispivotally connected to a ram which is supported by the distal endportion of the body so as to be slidable along the length of the body.When the drive member is in its inoperative condition, that is, in itsnon-pressed condition, the drive member is held in its folded condition,with its mid portion spaced away from the body. When the mid portion ofthe drive member is urged toward the body by the thumb of the operator,with the index finger held against the staple body, the drive member isextended from its folded condition. As a result, the distal end of thedrive member advances, so that the ram also advance to deform a staple.Since the foldable mid portion of the drive member is supported by thethumb, the stapler can not be supported by the operator in a stablemanner. In addition, the staple-deforming position is considerablyspaced away forwardly from the pressing force-applying position (i.e.,the manipulating position), and therefore when the pressing force isapplied to the drive member, the staple-deforming position may bevaried.

Japanese Patent Publication No. 46854/82 (corresponding to U.S. patentapplication Ser. No. 899,350 filed Apr. 24, 1978 and Ser. No. 26,071filed Apr. 3, 1979) discloses a stapler which is similar to the staplerdescribed in the above-mentioned Japanese Patent Publication No.164050/84 and has the same drawbacks.

A lightweight and small-size stapler is also disclosed in JapaneseLaid-Open Patent Application No. 82842/84 (corresponding to U.S. patentapplication Ser. No. 425,542 filed Sept. 28, 1982). In this conventionalstapler, a pair of levers are pivotally connected at their proximal endsto the proximal end portion of a body, and a pair of stapleformingelements are pivotally mounted on the distal end portion of the body.The distal ends of the levers are held in contact with thestaple-forming elements. When the distal end portions of the pair oflevers are pressed or urged by the thumb and the index finger,respectively, the staple-forming elements are pivotally moved at theirone ends, so that a staple is deformed by the other ends of thestaple-forming elements. This conventional stapler has no function ofincreasing the force applied by the operator. Therefore, this stapler isdisadvantageous in that the operator is required to exert a considerableforce to operate the stapler. This conventional stapler employs thestaple-forming elements pivotally mounted on the body, instead of alinearly movable ram, and in this respect this stapler is different inbasic construction from the stapler of the present invention.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a surgicalstapler which can be lightweight and be of a small size, and requiresless manipulating force for deforming a staple, and can deform thestaple in a stable manner.

According to one aspect of the present invention, there is provided asurgical stapler comprising:

(a) an elongated body;

(b) an anvil mounted on a distal end portion of the body;

(c) means for supporting a number of staples disposed in contiguousrelation to one another and for guiding the staples toward the anvil;

(d) means for urging the staples, supported on the support and guidemeans, toward the anvil;

(e) a ram mounted on the body so as to be movable toward and away fromthe anvil along a straight path extending along a longitudinal axis ofthe body, a leading one of the staples being disposed in the path andbeing disposed between the ram and the anvil;

(f) a lever pivotally connected at its proximal end to a proximal endportion of the body so as to be pivotally movable toward and away fromthe body, the lever having a manipulating portion at its distal endportion for pivotally moving the lever; and

(g) means for converting the pivotal movement of the lever into arectilinear movement of the ram along the path; the converting meansmoving the ram toward the anvil when the lever is pivotally moved towardthe body, so that the ram cooperates with the anvil to deform oppositeends of the leading staple toward each other; the lever acting on theconverting means at a mid portion of the lever disposed intermediate theproximal end of the lever and the manipulating portion, so that a forcegreater than a force applied to the manipulating portion can be appliedto the ram through the leverage of the lever.

According to another aspect of the present invention, there is provideda surgical stapler comprising:

(a) an elongated body having a guide passage;

(b) an anvil mounted on a distal end portion of the body;

(c) means for supporting a number of staples disposed in contiguousrelation to one another and for guiding the staples toward the anvil,the support and guide means communicating with the guide passage;

(d) means for urging the staples, supported on the support and guidemeans, toward the anvil, the urging means comprising an elongated urgingmember and a resilient member for urging the urging member toward thestaples, the urging member being received in the guide passage so as tobe slidingly movable along the guide passage, one end of the urgingmember being urged against a trailing one of the staples remote from theanvil, the guide passage having a curved portion, the urging member hasa flexible portion which can be guided by the curved portion, and theresilient member being engaged with that portion of the urging memberother than the one end of the urging member;

(e) a ram mounted on the body so as to be movable toward and away fromthe anvil along a straight path extending along a longitudinal axis ofthe body, a leading one of the staples being disposed in the path andbeing disposed between the ram and the anvil;

(f) a lever pivotally connected to the body so as to be pivotallymovable toward and away from the body; and

(g) means for converting the pivotal movement of the lever into arectilinear movement of the ram along the path; the converting meansmoving the ram toward the anvil when the lever is pivotally moved towardthe body, so that the ram cooperates with the anvil to deform oppositeends of the leading staple toward each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front-elevational view of a stapler provided in accordancewith the present invention, showing the manner of operating it;

FIG. 2 is a perspective view of the stapler;

FIG. 3 is an end view of the stapler as viewed in a direction of anarrow III of FIG. 2;

FIG. 4 is an enlarged front-elevational view of a distal end portion ofthe stapler as viewed in a direction of an arrow IV of FIG. 2;

FIG. 5 is a longitudinal cross-sectional view of the stapler;

FIG. 6 is a cross-sectional view taken along the line VI--VI of FIG. 5;

FIG. 7 is a cross-sectional view taken along the line VII--VII of FIG.5;

FIG. 8 is a front-elevational view of a pair of shell halvesconstituting a body of the stapler, as shown in their disassembledcondition;

FIG. 9 is a perspective view of the pair of shell halves as shown intheir disassembled condition;

FIG. 10 is a perspective view of a guide member having an anvil portion;

FIGS. 11A and 11B are perspective views of a staple-urging member,respectively, as viewed in different directions;

FIG. 12 is a perspective view of a cam follower;

FIG. 13A is a side-elevational view of a lever;

FIG. 13B is a front-elevational view of the lever; and

FIG. 14 is a longitudinal cross-sectional view of a modified stapler.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The invention will now be described with reference to the drawings.

FIGS. 1 and 2 show a surgical stapler of the disposable type whichcomprises an elongated hollow body 10 made of a resin. The overalllength of the body 10 is not more than 9 cm, and preferably 4 to 7 cm.The body 10 is composed of a pair of shell halves 10a and 10b connectedtogether by an adhesive or the like. As best shown in FIGS. 8 and 9, theshell halves 10a and 10b are substantially symmetrical in outer shapewith respect to the plane of connection between them. The shell half 10ahas a substantially flat wall 11 extending in the longitudinal axis ofthe body 10, a pair of opposed side walls 13a and 14a formedrespectively on the opposite lateral edges of the wall 11, and a pair ofopposed end walls 15a and 16a formed respectively on the opposite endedges of the wall 11. The walls 13a, 14a and 15a are flat and aredisposed substantially perpendicular to the wall 11. Similarly, theshell half 10b has a substantially flat wall 12 extending in thelongitudinal axis of the body 10, a pair of opposed side walls 13b and14b formed respectively on the opposite lateral edges of the wall 12,and a pair of opposed end walls 15 b and 16b formed respectively on theopposite end edges of the wall 12. The walls 13b, 14b and 15b are flatand are disposed substantially perpendicular to the wall 12. The walls11 and 12 are disposed in opposed relation to each other and serve asside walls of the body 10, respectively. As shown in FIG. 5, the walls13a and 13b jointly constitute a continuous side wall 13 of the body 10,and similarly the walls 14a and 14b jointly constitute a continuous sidewall 14 of the body 10. Thus, the body 10 has a tubular portion 18 of arectangular cross-section defined by the side walls 11 and 12 and theside walls 13 and 14. Also, the walls 15a and 15b jointly provide adistal end wall 15 of the body 10, and the walls 16a and 16b jointlyprovide a proximal end wall 16 of the body 10. The distal end wall 15 ofthe body 10 has a first portion 15' disposed in a plane perpendicular tothe longitudinal axis of the body 10, and a second portion 15" disposedin a plane inclined with respect to the longitudinal axis of the body10. The internal angle of the intersection between the two portions 15'and 15" are less than 180 degrees.

As shown in FIGS. 8 and 9, the corner portion of the shell half 10awhere the walls 15a and 14a are joined together is thickened to providea thickened portion 20a. The thickened portion 20a has an inner curvedsurface 21a and an inner flat surface 22a. A mounting groove 23a formounting a guide member 30 (later described) is formed in the flatsurface 22a. An inner wall 24a is formed on the inner surface of thewall 11, and extends along the wall 15a and 14a. That portion of theinner wall 24a corresponding to the curved surface 21a is curved. Thedistance between the inner wall 24a and the curved surface 21a as wellas the distance between the inner wall 24a and the wall 15a is smallerthan the distance between the inner wall 24a and the wall 15a. A notch25a is formed in that portion of the inner wall 24 a corresponding tothe curved surface 21a and the wall 15a, the notch 25a being formed inthe inner edge portion of the inner wall 24a remote from the wall 11.

The other shell half 10b has a thickened portion 20b which is disposedin symmetrical relation to the thickened portion 20a with respect to theplane of connection between the shell halves 10a and 10b. Like thethickened portion 20a, the thickened portion 20b has a curved surface21b, a flat surface 22b and a mounting groove 23b. Also, the shell half10b has an inner wall 24b having a notch 25b, the inner wall 24b beingdisposed in symmetrical relation to the inner wall 24a with respect tothe plane of connection between the shell halves 10a and 10b.

The inner walls 24a and 24b are mated together at their inner edges toprovide a guide wall 24 (see FIGS. 5 and 7). The guide wall 24 has aslot 25 defined by the notches 25a and 25b.

As shown in FIGS. 8 and 9, a notch 27a is formed in the corner portionof the shell half 10a where the wall 13a and the wall 15a are joinedtogether. Similarly, a notch 27b is formed in the corner portion of theshell half 10b where the wall 13b and the wall 15b are joined together,the notch 27b being disposed in symmetrical relation to the notch 27awith respect to the plane of connection between the shell halves 10a and10b. An opening 27 defined by the two notches 27a and 27b is provided inthe corner portion of the body 10 where the distal end wall 15 and thewall 13 are joined together (see FIGS. 1 to 5). The opening 27 has afirst portion 27' provided in the wall 13, and a second portion 27"provided in the distal end wall 15. As shown in FIGS. 3 and 4, thoseportions of the wall 13 respectively disposed immediately adjacent tothe opposite edges of the second portion 27" of the opening 27 serve asstoppers 29 and 29 for preventing a staple 40 from being disengaged fromthe body 10.

As shown in FIG. 5, the guide member 30 of steel is mounted on the body10 adjacent to its distal end. As shown in FIG. 10, the guide member 30has a flat base 31 of a rectangular shape, an insertion portion 32extending from one end of the base 31 in coplanar relation thereto, andan anvil portion 33 formed on the other end of the base 31, the anvilportion 33 being inclined with respect to the base 31. A pair of leg 34and 34 are formed respectively on the lateral edges of the base 31 andextend perpendicularly therefrom. A pair of abutment portions 35 and 35are formed respectively on one longitudinal edges of the leg 34 and 34remote from the base 31, and directed away from each other in parallelrelation to the base 31. The guide member 30 is disposed along thedistal end wall 15, with the insertion portion 32 received in themounting grooves 23a and 23b of the shell halves 10a and 10b. Theabutment portions 35 and 35 of the guide member 30 are held against theinner surface of the distal end wall 15. The anvil portion 33 of theguide member 30 is disposed in a plane perpendicular to the longitudinalaxis of the body 10, and is disposed in the opening 27.

As shown in FIG. 5, a guide groove 28 is provided along the guide wall24. The guide groove 28 has a first straight portion 28a formed by theguide wall 24 and the wall 14, a curved portion 28b formed by the guidewall 24 and the curved surfaces 21a and 21b of the shell halves 10a and10b, and a second straight portion 28c formed by the guide wall 24 andthe base 31 of the guide member 30.

A number of staples 40 are received in the second straight portion 28cof the guide groove 28, and are disposed in juxtaposed, contiguousrelation to one another. As shown in FIG. 4, the staple 40 is in theform of a generally U-shaped wire, and has a straight base 41 and a pairof legs 42 and 42 respectively extending perpendicularly from theopposite ends of the base 41 in the same direction. A distal end 42a ofeach leg 42 is pointed. The base 41 of each staple 40 is held in slidingcontact with and is guided by the base 31 of the guide member 30, thebase 41 being disposed perpendicular to the longitudinal axis of thebase 31. The pair of legs 42 are guided by the pair of leg 34 of theguide member 30, respectively.

An urging member 50 is received in the guide groove 28 of the body 10.The urging member 50 is made of a resin such as nylon, and has astrip-like base 51 which is greater in width at one end thereof toprovide a pair of arms 51a and 51a, as shown in FIGS. 11A and 11B. Apair of abutment portions 52 and 52 extend respectively from the distalends of the arms 51a and 51a in perpendicular relation to the base 51. Anumber of parallel grooves 53 are formed in one surface of that portion54 of the base 51 lying between the opposite end portions of the base51, and extend in the direction of the width of the base 51. The grooves53 are spaced from one another at an equal interval along the length ofthe base 51. Because of the provision of the transverse grooves 53, theportion 54 is flexible. A pair of parallel opposed projections 55 and 55are formed on the one surface of the flexible portion 54. The base 51 ofthe urging member 50 is received in the guide groove 28, and isslidingly movable therealong from its first straight portion 28a towardits second straight portion 28c. The abutment portions 52 and 52 of theurging member 50 are guided by the legs 34 and 34 of the guide member 30and is held against a trailing one of the staples 40 remote from theanvil portion 33. Since the flexible portion 54 can be easily deformedor curved when it is guided by the curved portion 28b of the guidegroove 28, the urging member 50 can be slidingly moved smoothly alongthe guide groove 28. The projections 55 and 55 extend through the slot25, formed through the guide wall 24, inwardly of the guide wall 24, andis movable along the slot 25.

The width of the guide groove 28 is slightly greater than the thicknessof the urging member 50 and the diameter of the staple 40, though thisis shown in an exaggerated manner in FIG. 5 for illustration purposes.

The urging member 50 is urged by a helical spring 60 toward the anvilportion 33 of the guide member 30. More specifically, a coil portion 61of the helical spring 60 provided at the central portion thereof isfitted on a cylindrical pin 65 formed on the shell half 10a, and one endof the helical spring 60 is engaged with a projection 66 formed on theshell half 10a whereas the other end is engaged with the projection 55of the urging member 50.

As shown in FIGS. 8 and 9, notches 67a and 67b are formed respectivelyin the edges of the walls 14a and 14b of the shell halves 10a and 10b.The notches 67a and 67b jointly provide an inspection window or opening67 (FIG. 5) through the wall 14 of the body 10. The inspection window 67is disposed in registry with the first straight portion 28a of the guidegroove 28, and the residual quantity of the staples 40 can be confirmedby viewing the position of the trailing end of the urging member 50,remote from the abutment portions 52 and 52, through the inspectionwindow 67. A scale may be provided on the urging member 50 adjacent toits trailing end to facilitate this visual confirmation.

As shown in FIGS. 8 and 9, an elongated projection 75a is formed on theinner surface of the wall 13a of the shell half 10a and extends alongthe longitudinal axis of the body 10. Another elongated projection 76ais formed on the inner surface of the wall 11 of the shell half 10a andextending in parallel opposed relation to the elongated projection 75a.A guide groove 77a is formed by the two projections 75a and 76a andopens at its one end to the opening 27. The height of the projection 76afrom the wall 11 is greater than the height of the projection 75a.Similarly, the other shell half 10b has elongated projections 75b and76b and a guide groove 77b which correspond to the elongated projections75a and 76a and the guide groove 77a and are disposed in registry withthem, respectively.

As shown in FIG. 5, a ram 70 is received in the guide grooves 77a and77b so as to be slidingly movable therealong. The ram 70 comprises asteel plate which has a rectangular base 71 and a pair of pressingprojections 72 and 72 formed on a front end of the base 71 in parallelspaced relation to each other, as shown in FIG. 12. The distance betweenthe pair of pressing projections 72 and 72 is greater than the width ofthe anvil portion 33 of the guide member 30 by an amount equal to orslightly greater than a value twice the diameter of the staple 40. Whenthe ram 70 advances, that is, moves toward the opening 27, the pressingprojections 72 and 72 press or urge the opposite end portions of thebase 41 of the staple 40 placed on the anvil portion 33, so that thebase 41 is bent as shown in dots-and-dash line in FIG. 4. The base 71 ofthe ram 70 has an engaging hole 73 formed therethrough for connecting acam follower 80 to the ram 70.

The cam follower 80 is connected to the ram 70. As shown in FIG. 12, thecam follower 80 has a rectangular plate-like base 81 composed of athickened portion 81a and a thinned portion 81b. A stepped portion 81cis provided between the thickened portion 81a and the thinned portion81b. A cam receiving portion 82 is formed on one surface of thethickened portion 81a of the base 81 and extends along the longitudinalaxis of the base 81. The cam receiving portion 82 has a semicylindricalend face 82a which serves as a cam receiving surface. A plate-likeretainer portion 83 extends from the other end of the cam receivingportion 82 in parallel, closely spaced relation to the thinned portion81b. A spring retainer portion 84 extends from the other end of the camreceiving portion 82 in a direction perpendicular to this portion 82. Anengaging projection 85 of a cylindrical shape is formed on one surfaceof the spring retainer portion 84 facing away from the cam receivingsurface 82a.

An engaging projection 86 is formed on one surface of the thinnedportion 81b facing the retainer portion 83. This engaging projection 86is fitted in the engaging hole 73 to thereby connect the ram 70 to thecam follower 80. Therefore, the ram 70 is moved together with the camfollower 80. For connecting the ram 70 to the cam follower 80, the base71 of the ram 70 is first inserted into a space between the thinnedportion 81b of the base 81 of the cam follower 80 and the retainerportion 83 in a direction of an arrow indicated in FIG. 12. When therear end of the base 71 of the ram 70 remote from the pressingprojections 72 and 72 is brought into engagement with a tapered surface86a on a front end of the engaging projection 86, the thinned portion81b and the retainer portion 83 are elastically deformed away from eachother to allow the insertion of the ram 70 therebetween. When theengaging projection 86 is fitted in the engaging hole 73 of the ram 70,the thinned portion 81b and the retainer portion 83 are returned totheir original shapes and are maintained parallel to each other, thuscompleting the connection between the ram 70 and the cam follower 80. Inthis condition, the rear end of the ram 70 is held against the steppedportion 81c.

As shown in FIG. 7, the outer surface of the base 81 of the cam follower80 are held in sliding contact with the inner surface of the wall 13whereas the inner surface of the base 81 are held in sliding contactwith the elongated projections 76a and 76b at its lateral marginalportions. Therefore, the base 81 is prevented from movement in thedirection of its thickness. Also, the opposite side or lateral edges ofthe base 81 are held in sliding contact with the elongated projections75a and 75b, respectively, so that the base 81 is prevented frommovement in the direction of its width. In other words, the cam follower80 is movable only in the direction of sliding of the ram 70.

Spring retainer portions 78a and 78b are formed on the shell halves 10aand 10b, respectively, and cooperate with each other to provide a singlespring retainer portion 78. As shown in FIG. 5, a compression coilspring 89 extends in a compressed condition between the spring retainerportion 78 and the spring retainer portion 84 of the cam follower 80.One end of the coil spring 89 is fitted on the engaging projection 85 ofthe cam follower 80. The cam follower 80 and the ram 70 are urged by thecoil spring 89 away from the anvil portion 33 of the guide member 30.

Next, a lever 90 will now be described. The lever 90 is molded of aresin. As shown in FIGS. 13A and 13B, the lever 90 has a pivot pinportion 91 at its proximal end, a flat manipulating portion(pressure-applying portion) 92 at its distal end portion, and aplate-like connective portion 93 interconnecting the pivot pin portion91 and the manipulating portion 92. The lever 90 further has a pair ofparallel, opposed plate-like cams 94 and 94 formed on the opposite sidesof the connective portion 93, the cams 94 and 94 being disposedperpendicular to the connective portion 93. The cams 94 and 94 extend tothe underside of the manipulating portion 92. As shown in FIG. 13A, eachcam 94 has a generally triangular shape, and has a first cam surface 94aon its edge in the vicinity of the apex of such a triangle, and a secondcam surface 94b formed by the edge of the cam 94 and extending from thefirst cam surface 94a toward the manipulating portion 92. Each of thefirst and second cam surfaces 94a and 94b is flat. One side or edge 94xof the generally triangular cam 94 is disposed in a line passing throughthe axis of the pivot pin portion 91. The angle θ2 formed by this lineand the second cam surface 94b is greater than the angle θ`formed bythis line and the first cam surface 94a.

The proximal end portion of the body 10 has the function of a bearingfor supporting the lever 90. More specifically, as shown in FIGS. 8 and9, a pair of bearing portions 95a and 95a are formed on the wall 16a ofthe shell half 10a, and also a pair of bearing portions 95b and 95b areformed on the wall 16b of the shell half 10b. A U-shaped notch 95c isformed in each of the bearing portions 95b and 95b. The notch 95c ineach bearing portion 95b defines, together with its mating bearingportion 95a, a bearing hole, and as shown in FIG. 6, the opposite endsof the pivot pin portion 91 of the lever 90 are extended through thesebearing holes, respectively, so that the lever 90 is pivotally supportedon the body 10. An opening 96 is formed through the wall 12 of the shellhalf 10b, and the lever 90 extends outwardly from the body 10 throughthe opening 96. When the lever 90 is in its inoperative condition, thatis, in its non-pressed condition, the lever 90 is extended toward thedistal end of the body 10 at a predetermined angle with respect to thebody 10. One edge 96a of the opening 96 disposed near the wall 16bserves as a stopper surface, the stopper surface 96a being inclinedrelative to the wall 12. Also, another edge 96b of the opening 96disposed in opposed relation to the edge 96a serves as another stoppersurface, the stopper surface 96b being disposed perpendicular to thewall 12. The stopper surface 96a limits the pivotal movement of thelever 90 away from the body 10 whereas the other stopper surface 96blimits the pivotal movements of the lever 90 toward the body 10. Theoverall length of the lever 90 is equal to or smaller (as in theillustrated embodiment) than that of the body 10. If the lever 90 isshorter than the body 10, it is preferred that the difference betweenthe two is not more than 3 cm. The pivot pin portion 91 of the lever 90is disposed perpendicular to the base 41 of each staple 40 and is alsodisposed perpendicular to the direction of movement of the ram 70.

As shown in FIG. 6, either of the first and second cam surfaces 94a and94b of each cam 94 of the lever 90 is always disposed in tangentialcontact with the cam receiving surface 82a of the cam follower 80. Thecams 94 and 94 of the lever 90 and the cam follower 80 jointlyconstitute a cam mechanism 99.

When the lever 90 is in its inoperative position, the cam follower 80 isheld in its retracted position by the coil spring 89, and therefore theram 70 is also in its retracted position and is spaced apart from thestaple 40 supported by the anvil portion 33 of the guide member 30. Inthis condition, since the coil spring 89 acts on the lever 90 throughthe cam follower 80, the connective portion 93 is urged against thestopper surface 96a to thereby maintain the lever 90 at thepredetermined angle with respect to the body 10, with the manipulatingportion 92 considerably spaced apart from the body 10. In thisinoperative condition of the lever 90, the first cam surfaces 94a and94a of the lever 90 are held in contact with the cam receiving surface82a of the cam follower 80.

When a wound or the like is to be sutured or sewed up by the surgicalstapler of the above construction, the stapler is disposed in agenerally triangular space formed by the thumb A and index finger B, forexample, of the right hand of the operator, with the proximal end of thebody 10 disposed at the fork portion where the thumb A and the indexfinger are joined together, and the thumb A is held against themanipulating portion 92 of the lever 90 whereas the index finger B (ifnecessary, together with the middle finger) is held against the wall 11of the body 10. Then, the first portion 15' of the distal end wall 15 ofthe body 10 is brought into contact with the surface of the body of thepatient in such a manner that the thumb A is directed toward theoperator, with the index finger B directed away from the operator. Inthis condition, the opening 27 is disposed on the left side as viewedfrom the operator, and the view of the opening 27 (i.e., the position ofdeforming the staple 40) is not obstructed by the hand of the operator.

In this condition, the manipulating portion 92 of the lever 90 ispressed or urged toward the body 10 to pivotally move the lever 90 aboutthe pivot pin portion 91. As a result, the pivotal movement of the lever90 is converted into a rectilinear movement of the ram 70 through thecams 94 and 94 and the cam follower 80, that is, through the cam action,caused by the first cam surfaces 94a and 94a and the camreceivingsurface 82a, and the subsequent cam action caused by the second camsurfaces 94b and 94 and the cam-receiving surface 82a. As a result, theram 70 advances toward the staple 40 supported on the anvil portion 33of the guide member 30. Since the inclination angle θ1 of each first camsurface 94a is smaller while the inclination angle θ2 of each second camsurface 94b is greater, the amount of movement of the ram 70 per unitamount of pivotal movement of the lever 90 is greater at an initialstage of this pivotal movement of the lever 90 (that is, when the firstcam surfaces 94a and 94a are held in contact with the cam-receivingsurface 82a). Therefore, with a small amount of the pivotal movement ofthe lever 90, the ram 70 can be brought into contact with the staple 40supported on the anvil portion 33. Immediately before the ram 70 isbrought into contact with the staple 40, the second cam surface 94b and94b are brought into contact with the cam-receiving surface 82a. Then,when the lever 90 is further pivotally moved, the pressing projections72 and 72 of the ram 70 press the staple 40 to deform it as describedabove. At this deforming stage, the amount of movement of the ram 70 perunit amount of pivotal movement of the lever 90 is smaller, since thesecond cam surfaces 94b and 94b are disposed in contact with thecam-receiving surface 82a, and the cam mechanism 99 performs aforce-increasing function. The manipulating force applied to themanipulating portion 92 of the lever 90 is increased through theleverage of the lever 90 and is transmitted to the cams 94 and 94.Because of the leverage of the lever 90 and the force-increasingfunction of the cam mechanism 99, the deformation of the staple 40 canbe achieved with a relatively small manipulating force applied by theoperator.

When the cam follower 80 is urged by the pivotally-moving lever 90, thecam follower 80 is also subjected to a force acting in a directionperpendicular to the direction of sliding movement of the ram 70.However, this force is received by the elongated projections 75a and 75bthrough the opposite side edges of the base 81 of the cam follower 80,and therefore this force does not act on the ram 70, so that the ram 70is prevented from deformation and is also prevented from displacinglaterally out of position.

In addition, the thumb A presses against the manipulating portion 92,and this manipulating force-applying position is relatively near to thestaple deforming position. Therefore, the deformation of the staple 40can be carried out in a stable manner.

Further, the direction of movement of the manipulating portion 92 of thelever 90 toward the body 10 is the same as the direction of deformationof the pair of legs 42 and 42 of the staple 40 toward each other.Therefore, the operator feels as if he deformed the staple 40 directlyby the hand, thus providing a good operability.

The pivotal movement of the lever 90 toward the body 10 is limited uponcontact of the cams 94 and 94 with the stopper surface 96b of the body10.

When the pressing or urging of the lever 90 is released, the camfollower 80, the ram 70 and the lever 90 are returned to theirrespective original positions under the influence of the coil spring 89.

As described above, since the stapler is of such a construction that thestapler can be held between the thumb and the index finger heldrespectively against the lever 90 and the body 10, the stapler can belightweight and of a small size.

Since the guide groove 28 for guiding the movement of the urging member50 has the curved portion 28b, the first and second straight portions28a and 28c can be arranged in angular relation to each other so as toextend along the wall 14 and the distal end wall 15, respectively. Withthis arrangement, the width of the body 10 can be smaller as comparedwith the case where the guide groove 28 is straight over the entirelength thereof. This also enables the body 10 to be lightweight and of asmall size.

As shown in FIG. 4, when the base 41 of the staple 40 is bent throughthe cooperation of the ram 70 with the anvil portion 33, the pair oflegs 42 and 42 of the staple 40 are angularly moved toward each otherand are extended outwardly from the distal end wall 15 through thesecond portion 27" of the opening 27 formed through the body 10, so thatthe pair of legs 42 and 42 are put or driven into the body of thepatient on the opposite sides of the wound C and is retained there.

Then, when the stapler is moved in a right-hand direction as viewed fromthe operater, the thus applied staple 40 is brought out of engagement ofthe anvil portion 33 and is discharged from the body 10 through thefirst portion 27' of the opening 27, so that the staple 40 remains inthe body of the patient.

When the staple 40 is discharged from the anvil portion 33, the group ofjuxtaposed staples 40 supported on the guide member 30 are urged towardthe anvil portion 33 under the influence of the helical spring 60, sothat the leading staple 40 is disposed in the path of movement of theram 70.

The above staple-applying operation is repeated, so that the staples 40are sequentially put into the body of the patient along the wound C,thereby suturing or sewing up the wound C.

FIG. 14 shows a modified stapler which differs from the stapler of thepreceding embodiment in that a cam-receiving portion 182 of a camfollower 180 is of a cylindrical shape, that a guide wall 124 does nothave the slot 25 and instead has a rounded portion adjacent to thecurved portion 28b of the guide groove 28 so as to provide a generallycircular container portion 125, and that a spiral spring 160 of a stripis accommodated within the container portion 125, the spiral spring 160having one free end. The distal end portion of the spiral spring 160 isreceived in and extends along the first straight portion 28a of theguide groove 28, and the other or distal end 160a of this spring isconnected to the rear end of a urging member 150. More specifically, thedistal end 160a of the spiral spring 160 is bent into a right-angularshape and is engaged in a hole formed through the rear end of the urgingmember 150. The urging member 150 is not provided with the projection55. The urging member 150 urges the staples 40 toward the anvil portion33 under the influence of the spiral spring 160.

The cam follower may be formed integrally with the ram. The lever mayhave more than two cam surfaces. Also, the cam surface may be formed bya curved surface whose radius of curvature is gradually varied.

What is claimed is:
 1. A surgical stapler comprising:(a) an elongatedbody; (b) an anvil mounted on a distal end portion of said body; (c)means for supporting a number of staples disposed in contiguous relationto one another and for guiding said staples toward said anvil; (d) meansfor urging said staples, supported on said support and guide means,toward said anvil; (e) a ram mounted on said body so as to be movabletoward and away from said anvil along a straight path extending along alongitudinal axis of said body, a leading one of said staples beingdisposed in said path and being disposed between said ram and saidanvil; (f) a lever pivotally connected at its proximal end to a proximalend portion of said body so as to be pivotally movable toward and awayfrom said body, said lever having a manipulating portion at its distalend portion for pivotally moving said lever; and (g) means forconverting the pivotal movement of said lever into a rectilinearmovement of said ram along said path; said converting means moving saidram toward said anvil when said lever is pivotally moved toward saidbody, so that said ram cooperates with said anvil to deform oppositeends of said leading staple toward each other; said lever acting on saidconverting means at a mid portion of said lever disposed intermediatethe proximal end of said lever and said manipulating portion, so that aforce greater than a force applied to said manipulating portion can beapplied to said ram through the leverage of said lever, in which saidbody comprises a tubular portion of a generally rectangularcross-section having a pair of generally parallel, opposed first andsecond side walls, and a pair of generally parallel, opposed third andfourth side walls, and distal end wall closing a distal end of saidtubular portion; there being provided an opening formed through a cornerportion of said body where said first side wall and said distal end wallare joined together; said anvil being disposed in the vicinity of saidopening; the opposite ends of said staple deformed by said ram and saidanvil extending outwardly from said body through said opening; saiddeformed staple being discharged from said body through said opening;said support and guide means extending along said distal end wall; saidpath of movement of said ram extending along said first side wall; theaxis of pivotal movement of said lever being disposed perpendicular tosaid first and second side walls; there being provided another openingformed through said third side wall; the proximal end portion of saidlever being disposed within said body; and said lever extendingoutwardly from said body through said another opening.
 2. A surgicalstapler comprising:(a) an elongated body; (b) an anvil mounted on adistal end portion of said body; (c) means for supporting a number ofstaples disposed in contiguous relation to one another and for guidingsaid staples toward said anvil; (d) means for urging said staples,supported on said support and guide means, toward said anvil; (e) a rammounted on said body so as to be movable toward and away from said anvilalong a straight path extending along a longitudinal axis of said body,a leading one of said staples being disposed in said path and beingdisposed between said ram and said anvil; (f) a lever pivotallyconnected at its proximal end to a proximal end portion of said body soas to be pivotally movable toward and away from said body, said leverextending toward said distal end portion of said body at a predeterminedangle to said body when in a non-pressed state and said lever having amanipulating portion at its distal end portion for pivotally moving saidlever; and (g) means for converting the pivotal movement of said leverinto a rectilinear movement of said ram along said path; said convertingmeans moving said ram toward said anvil when said lever is pivotallymoved toward said body, so that said ram cooperates with said anvil todeform opposite ends of said leading staple toward each other; saidlever acting on said converting means at a mid portion of said leverdisposed intermediate the proximal end of said lever and saidmanipulating portion, so that a force greater than a force applied tosaid manipulating portion can be applied to said ram through theleverage of said lever.
 3. A surgical stapler according to claim 2, inwhich said converting means includes a cam means for increasing theforce applied to said mid portion of said lever when said lever ispivotally moved toward said body and for transmitting said increasedforce to said ram.
 4. A surgical stapler according to claim 3, in whichsaid cam means comprises a cam formed on said mid portion of said lever,and a cam follower which is connected to said ram and is disposed incontact with said cam.
 5. A surgical stapler comprising:(a) an elongatedbody; (b) an anvil mounted on a distal end portion of said body; (c)means for supporting a number of staples disposed in contiguous relationto one another and for guiding said staples toward said anvil; (d) meansfor urging said staples, supported on said support and guide means,toward said anvil; (e) a ram mounted on said body so as to be movabletoward and away from said anvil along a straight path extending along alongitudinal axis of said body, a leading one of said staples beingdisposed in said path and being disposed between said ram and saidanvil; (f) a lever pivotally connected at its proximal end to a proximalend portion of said body so as to be pivotally movable toward and awayfrom said body, said lever having a manipulating portion at its distalend portion for pivotally moving said lever; and (g) means forconverting the pivotal movement of said lever into a rectilinearmovement of said ram along said path; said converting means moving saidram toward said anvil when said lever is pivotally moved toward saidbody, so that said ram cooperates with said anvil to deform oppositeends of said leading staple toward each other; said lever acting on saidconverting means at a mid portion of said lever disposed intermediatethe proximal end of said lever and said manipulating portion, so that aforce greater than a force applied to said manipulating portion can beapplied to said ram through the leverage of said lever, in which saidcam has a first cam surface and a second cam surface which extends fromsaid first cam surface toward the distal end of said lever, an amount ofmovement of said ram per unit amount of pivotal movement of said leverbeing smaller when said cam follower is disposed in contact with saidsecond cam surface than when said cam follower is disposed in contactwith said first cam surface.
 6. A surgical stapler comprising:(a) anelongated body having a guide passage; (b) an anvil mounted on a distalend portion of said body; (c) means for supporting a number of staplesdisposed in contiguous relation to one another and for guiding saidstaples toward said anvil, said support and guide means communicatingwith said guide passage; (d) means for urging said staples, supported onsaid support and guide means, toward said anvil, said urging meanscomprising an elongated urging member and a resilient member for urgingsaid urging member toward said staples, said urging member beingreceived in said guide passage so as to be slidingly movable along saidguide passage, one end of said urging member being urged against atrailing one of said staples remote from said anvil, said guide passagehaving a curved portion, said urging member having a flexible portionwhich can be guided by said curved portion, and said resilient memberbeing engaged with that portion of said urging member other than saidone end of said urging member; (e) a ram mounted on said body so as tobe movable toward and away from said anvil along a straight pathextending along a longitudinal axis of said body, a leading one of saidstaples being disposed in said path and being disposed between said ramand said anvil; (f) a lever pivotally connected to said body so as to bepivotally movable toward and away from said body; and (g) means forconverting the pivotal movement of said lever into a rectilinearmovement of said ram along said path; said converting means moving saidram toward said anvil when said lever is pivotally moved toward saidbody, so that said ram cooperates with said anvil to deform oppositeends of said leading staple toward each other, in which said bodycomprises a tubular portion of a generally rectangular cross-sectionhaving a pair of generally parallel, opposed first and second sidewalls, and a pair of generally parallel, opposed third and fourth sidewalls, and a distal end wall closing a distal end of said tubularportion; there being provided an opening formed through a corner portionof said body where said first side wall and said distal end wall arejoined together; said anvil being disposed in the vicinity of saidopening; the opposite ends of said staple deformed by said ram and saidanvil extending outwardly from said body through said opening; saiddeformed staple being discharged from said body through said opening;said support and guide means extending along said distal end wall; saidpath of movement of said ram extending along said first side wall; saidcurved portion of said guide passage being disposed in the vicinity of acorner portion of said body where said second side wall and said distalend wall are joined together; and said guide passage also having astraight portion extending along said second side wall.
 7. A surgicalstapler according to claim 6, in which a projection is formed on saidflexible portion of said urging member, said resilient member comprisinga helical spring disposed inwardly of said curved portion of said guidepassage, and one end of said helical spring acting on said projection.8. A surgical stapler according to claim 6, in which said resilientmember comprises a spiral spring, a container portion being formed onthe body inwardly of an adjacent to said curved portion of said guidepassage, said spiral spring being accommodated within said containerportion, and one end of said spiral spring acting on the other end ofsaid urging member remote from said staples.
 9. A surgical staplercomprising:(a) an elongated body; (b) an anvil mounted on a distal endportion of said body; (c) means for supporting a number of staplesdisposed in contiguous relation to one another and for guiding saidstaples toward said anvil; (d) means for urging said staples, supportedon said support and guide means, toward said anvil; (e) a ram mounted onsaid body so as to be movable toward and away from said anvil along astraight path extending along a longitudinal axis of said body, aleading one of said staples being disposed in said path and beingdisposed between said ram and said anvil; (f) a lever pivotallyconnected at its proximal end to a proximal end portion of said body soas to be pivotally movable toward and away from said body, said leverhaving a manipulating portion at its distal end portion for pivotallymoving said lever; and (g) means for converting the pivotal movement ofsaid lever into a rectilinear movement of said ram along said path; saidconverting means moving said ram toward said anvil when saidmanipulating portion of said lever is moved toward said body, so thatsaid ram cooperates with said anvil to deform opposite ends of saidleading staple toward each other; a direction of movement of saidmanipulating portion of said lever toward said body being the same as adirection of deformation of said opposite end of said staple toward eachother.
 10. A surgical stapler according to claim 9, in which saidstapler has a size such that said stapler can be disposed in a generallytriangular space formed by a thumb and index finger of a hand of anoperator of said stapler with said proximal end of said body beingdisposed at a fork portion where the thumb and the index finger of thehand of the operator are joined together, the thumb being held againstsaid manipulating portion of said lever and the index finger being heldagainst said body.
 11. A surgical stapler according to claim 2, in whichsaid body has a length of not more than 9 cm, the length of said leverbeing not more than the length of said body.